1. Field of the Disclosure
The disclosure relates to a medical, in particular a dental-medical, handpiece having an elongate grip with a sleeve for clamping a tool.
2. Related Technology
A handpiece of this kind is described in DE 29 23 358 C2. This known handpiece has a clamping sleeve, round in cross-section, which is rotationally fixed in a rotary bearing sleeve, wherein an inner space surrounded by the rotary bearing sleeve forms a sleeve receiving space for the clamping sleeve. The clamping sleeve has in a middle longitudinal region a constriction section and four slots taking in the entire wall thickness of the hollow cylindrical wall and distributed on the circumference, with which the clamping sleeve forms a so-called split chuck, into which a tool can be inserted and clamped with a shaft. The clamping sleeve thus forms a coupling, effective both in the axial direction and in the circumferential direction of the tool, for holding the tool shaft by means of elastically yielding clamping with the clamping webs present between the slots. The external circumference of the clamping sleeve is so strongly waisted in the region of the clamping webs that upon insertion of the tool shaft into the clamping sleeve the clamping webs can radially bend outwardly into the free space formed by the waist. Further, the rotary bearing sleeve and the clamping sleeve arranged therein can selectively be so mounted in the handpiece that their common middle axis extends longitudinally or transversely in the handpiece.
In U.S. Pat. No. 5,496,218 there is described a dental-medical handpiece having a tool attachment part which with its rear end region can be selectively placed on the forward end region of a grip sleeve, and pulled off again. The attachment part has at its free end a rotatably mounted polishing tool which stands in driving connection with a cylindrical drive pin coaxially rotatably mounted in the rearward end region of the attachment part. Upon placing of the tool attachment part, the drive pin is, with radially inwardly directed clamping tension, pushed into an inner longitudinally slotted clamping sleeve, which is formed by means of the forward end region of a drive shaft rotatably mounted coaxially in the grip sleeve. On the inner clamping sleeve there sits, likewise with radially inwardly directed clamping tension, a likewise longitudinally slotted outer sleeve which is surrounded by a free space of an axial bore in the grip sleeve receiving the drive shaft, so that upon insertion of the drive pin into the inner clamping sleeve both sleeves can expand radially.
With a handpiece of the kind concerned there is desired in particular in its forward end region a small cross-sectional size, in order to be able to use the handpiece also in body cavities of patients, e.g. in the mouth, while ensuring an adequate view of the treatment site. Further, a sufficiently large clamping force for clamping the tool shaft is necessary in order to ensure, in functional operation, that the tool is carried along in rotation.